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Sequence determining the parity of A025748.
0

%I #5 Jan 16 2013 07:48:37

%S 0,8,32,40,128,136,160,168,512,520,544,552,640,648,672,680,2048,2056,

%T 2080,2088,2176,2184,2208,2216,2560,2568,2592,2600,2688,2696,2720,

%U 2728,8192,8200,8224,8232,8320,8328,8352,8360,8704,8712,8736

%N Sequence determining the parity of A025748.

%C Odd terms occur in A025748 at positions (0),1,2,3,(8),9,10,11,(32),33,34,35,(40),...

%F a(n)=8*A000695(n); a(n)=4*sum{k=0..floor(log_2(n+1)), mod(floor(n/2^k),2)2^(2k+1)};

%K easy,nonn

%O 0,2

%A _Paul Barry_, Feb 09 2007